B4 Organising animals and plants Flashcards
What are the components of blood?
Plasma- red blood cells, white blood cells, platelets
Dissolved substances
What is the functions of blood plasma?
- yellow liquid
- transports blood cells + substances around body
- waste CO2 carried from cells to lungs
- Urea (from liver), carried to kidneys, from blood to urine
- small soluble products of digestion pass to plasma from small intestine to cells
What are the adaptations of red blood cells?
- more rbc than any type of blood cell
- take oxygen from air in lungs, to cells
- biconcave shape, increase SA to V ration for diffusion
- Haemoglobin (red pigment), binds to oxygen
- no nucleus, more space for haemoglobin
How is oxygen transported from red blood cells to body cells?
lungs- Haemoglobin binds to oxygen = oxyhaemoglobin
body tissues- oxyhaemoglobin splits to haemoglobin and oxygen, releases oxygen to cells
What are the functions of white blood cells?
- bigger than red blood cells, less of them in blood
- nucleus
- part of body defence system against harmful microorganisms
- lymphocytes form antibodies against microorganisms, form antitoxins
- phagocytes engulf + digest invading bacteria/viruses
What are the functions of platelets?
- small fragments of cells
- no nucleus
- help blood clot at wounds
What is the process of blood clotting?
series of enzyme-controlled reactions
- convert fibrinogen into fibrin
- network of protein fibres, capture rbc + morre platelets
- form clot, stops bleeding
- scab protects new growing skin, stops bacteria entering body
What makes up the human circulatory system?
Blood, blood vessels, heart
What are the 3 main types of blood vessels in the body?
Arteries, Veins, Capillaries
What direction to arteries carry blood?
OX blood, Away from the heart, towards body organs
- pulmonary artery= DEOX blood
What direction to veins carry blood?
OX blood, INto the heart, from body organs
- pulmonary vein= DEOX blood
What is the function of valves in veins?
Prevent the backflow of blood
What is the function of capilliaries?
- huge network of tiny vessels
- link the arteries and the veins
- thin walls, easy diffusion (oxygen, glucose, CO2)
What are the features of arteries?
- Thick walls
- Small lumen
- Thick layer of muscle and elastic fibre
What are the features of veins?
- Thin walls
- Large lumen
- often have valves
What are the features of capillaries?
- 1 cell thick walls
- tiny vessel
- narrow lumen
What is a Double circulatory system?
The separation of 2 systems where one carries blood from the heart to the lungs and back, and the other carried blood from the heart to all other organs of the body and back
What effect does leaky valves have on a person?
- valves become stiff, do not open fully. Heart is less efficient
- become breathless, can die
What are mechanical valves?
man made valves
ie titanium, polymers
What are biological valves?
valves from pigs, cows or humans
What are the pos/neg of Mechanical valves?
P- long lasting
N- life long medication, prevent blood clotting around it
What are the pos/neg of Biological valves?
P- work very well, no medication needed
N- only last 12-15 years
What is an Artificial pacemaker?
An electrical device used to correct irregularities in heart rate
- implanted into chest, wires running to heart
What is a Natural Pacemaker?
a group of cells in the right atrium that control the resting heartbeat of a human
What are the effects of a faulty N pacemaker?
Too slow- not enough oxygen
Too fast- doesn’t pump blood properly
How does an artificial pacemaker work?
- Light
- attached to heart by 2 wires
- sends strong, regular electrical signals to heart, stimulating it to beat
What are the pos/neg of Artificial pacemakers?
P- increase quality of life + length of life
N- regular medical checkups throughout life
Why do many people die waiting for a heart transplant?
They need a donor heart that is a tissue match, hard to find
What is an artificial heart?
temporary hearts, can support natural hearts until replacement
What are the pos/neg of artificial hearts?
P- lead a more normal life, higher chance of living until surgery, give diseased heart a rest
N- lots of machinery to work, may have to stay in hospital until transplant, risk of blood clotting (death), high costs to develop
How is the heart muscle supplied with oxygen?
Coronary arteries
What is the process of the heart pumping blood?
- blood enters atria: right- vena cava, deox. left- pulmonary vein, ox
- atria contract, force blood down ventricles, valves close (prevent backflow)
- ventricles contract, force blood out: right- pulmonary artery, deox to lungs. left- aorta, ox to body organs
- flows to organs, comes back to heart, blood re enters atria
Why is the muscle wall of the left ventricle thicker than the right?
allows left ventricle to develop pressure needed to force blood around the body
How does coronary heart disease affect blood flow through the heart?
- coronary arteries build up fatty material, become narrow, supply less blood to heart.
- cause pain, heart attack, death
What is a stent?
metal mesh placed in the artery to hold the blood vessel open
What is bypass surgery?
- replace narrow or blocked coronary arteries with vein
- works where stents cannot be used
- can be expensive, risky
What are statins?
- reduce blood cholesterol levels, slow down rate of fatty build up and reduce risk of coronary heart disease
Where are the lungs found and what are they protected by?
found- thorax
protected- ribcage
How are the lungs separated from the rest of the body?
the diaphragm- strong sheet of muscle
What are the different types of plant tissue?
Epidermal tissue
Palisade mesophyll tissue
Spongy mesophyll tissue
Xylem
Phloem
Meristem tissue
What is the uses for each of the plant tissues?
Epidermal tissue- covers + protects surfaces, secrete waxy substances to waterproof leaf
Palisade mesophyll tissue- contains many chloroplasts for photosynthesis
Spongy mesophyll tissue- contains some chloroplasts, big air spaces + large SA for easy diffusion
Xylem + Phloem- transport substances around plants
Meristem tissue- rapidly diving plant cells, grow and differentiate to all other cell types (found in growing roots and shoots tips)
What is the role of Xylem?
carry water + dissolved mineral ions from roots to the stem and leaves
What is the role of Phloem?
transport dissolves sugars from the leaves to the rest of the plant, including areas of growth and storage (for winter)
What are the different plant organs + their roles?
Leaf- carries out photosynthesis
Stem- supports leaves + flowers
Roots- take up water + minerals from soil
What do the Roots, Stems and Leaves form to make?
An organ system- transport of substances around the plant
What is the order of tissues in a leaf? (top to bottom)
Upper epidermis
Palisade mesophyll
Spongy mesophyll
Lower epidermis- stomata, guard cells
What is Translocation?
the movement of dissolved sugars from the leaves to the rest of the plant
Why is transport in plants so important?
-All cells need glucose for respiration and materials for growth
- mineral ions (water) : production of protein + molecules within cells
- water for photosynthesis, hold itself upright
How does a young plant/soft stemmed plant hold itself upright, in terms of water?
- cell has plenty of water, vacuole presses cytoplasm up against cell wall
- pressure gives support to young plants + leaf structure
What are Stomata + what is their role?
- small openings on the leaf
- can be opened when a plant needs to allow air into/out the leaf
- allowing carbon dioxide in when letting water vapour out
What are Guard cells?
cells that control the size, and opening/closing of stomata
How is a concentration gradient maintained in a leaf?
- CO2 from atmosphere diffuses into air spaces, into leaf, down a concentration gradient
- Oxygen (from photosynthesis) leaves by diffusion into air
- maintains a concentration gradient
What is Transpiration?
The loss of water vapour from the surface of plant leaves
What do stomata and guard cells control?
gas exchange and water loss
- important guard cells can close, to reduce the loss of water vapour
What is the transpiration stream?
Water evaporates from the surface of the leaves, more water is pulled up the xylem
- driven by water evaporation from leaves
What are the factors that affect the rate of transpiration?
Temperature, Humidity, Amount of Air Movement, Light Intensity
Why does increasing rate of photosynthesis increase rate of transpiration?
- more stomata open to let carbon dioxide in
- increases rate water is lost by evaporation + diffusion
Why does increasing rate of evaporation increase rate of transpiration?
- Hot, dry, windy conditions increase rate of transpiration (more water evaporation, quicker diffusion)
-dry: concentration gradient is steeper, quick diffusion of water vapour
-windy: removes water from leaf as it diffuses
How does temperature increase the rate of transpiration?
- molecules more faster as temp increases, more rapid diffusion
- rate of photosynthesis increases, more stomata open
How do plants control water loss whilst maximising photosynthesis?
- waxy waterproof cuticle layer, prevent uncontrollable water loss
- most stomata on the underside (protect from sun energy + direct light)
- wilting (leaves collapse + hang down, reduces SA for water loss by evaporation)
- Stomata close, stop photosynthesis + risk overheating BUT most prevents water loss + further wilting)
What conditions does a plant need to stop wilting ?
Temperature drop, sun goes in/night time, rains
What is the job of the ventilation system?
- move air in and out of lungs
- provides efficient surface for gas exchange in alveoli
How does ventilating the lungs occur?
Contraction and relaxation of intercostal muscles, change pressure in chest cavity, air is forced in or out of lungs due to difference in pressure
How does air enter the lungs (breathing in) in terms of pressure?
- atmospheric air at higher pressure than chest, air drawn into lungs
- increased volume= lower pressure in chest
- ribs move up and out, diaphragm flattens, volume of chest increases
How does air exit the lungs (breathing out) in terms of pressure?
- pressure in chest is higher than outside, air is forced out of lungs
- decreased volume = increased pressure in chest
- ribs fall, diaphragm moves up, volume of chest decreases
How are lungs adapted for efficient gas exchange?
Alveoli
- large SA, efficient diffusion of oxygen + CO2
- good blood supply from capillaries, maintain steep concentration gradient (rapid + effective gas exchange)
- 1 cell thick layer between air and blood in capillaries (short diffusion distance)
